In the field of printing, the most common type printer has been the printer which impacts against record media that is caused to be moved past a printing line or line of printing. As is well-known, the impact printing operation depends upon the movement of impact members, such as print hammers or wires or the like, which are typically moved by means of an electromechanical-type drive system and which system enables precise control of the impact members.
In the field of dot matrix printers, it has been quite common to provide a print head which has included therein a plurality of print wire actuators or solenoids arranged or grouped in a manner to drive the respective print wires a very short, precise distance from a rest or non-printing position to an impact or printing position. The print wires are generally either secured to or engaged by the solenoid plunger or armature which is caused to be moved such precise distance when the solenoid coil is energized and wherein the armature or plunger normally operates against the action of a return spring.
It has also been quite common to provide an arrangement or grouping of such solenoids in a circular configuration to take advantage of reduced space available in the manner of locating the print wires in that specific area between the solenoids and the front tip of the print head adjacent the record media. In this respect, the actuating ends of the print wires are positioned in accordance with the circular arrangement and the operating or working ends of the print wires are closely spaced in vertically-aligned manner adjacent the record media. The availability of narrow or compact actuators permits a narrower or smaller print head to be used and thereby reduces the width of the printer because of the reduced clearance at the ends of the print line. The print head can also be made shorter because the narrow actuators can be placed in side-by-side manner closer to the record media for a given amount of wire curvature.
In the wire matrix printer which is utilized for receipt, journal and slip printing operation, the print head structure may be a multiple element type and horizontally disposed with the wire elements aligned in a vertical line and supported on a print head carriage which is caused to be moved or driven in a horizontal direction for printing in line manner across the receipt or journal paper and wherein the drive elements or transducers may be positioned in a circular configuration with the respective wires leading to the front tip of the print head. In the wire matrix printer which is utilized for business forms or like record media printing operation, the print head may be oriented in a manner wherein the nose is pointed downward for printing on the form, slip or record media while the carriage and print head are moved above and across the form or media in the horizontal direction.
Further, the printer structure may be an arrangement which includes a plurality of equally-spaced, horizontally-aligned, single element print heads which are caused to be moved in back and forth manner to print successive lines of dots in making up the lines of characters. In this latter arrangement, the drive elements or transducers are individually supported along a line of printing. Dependent upon the printer type, the horizontally-aligned, single element print heads may be either horizontally or vertically oriented in the axial direction for printing operation. These single wire actuators or solenoids are generally tubular or cylindrically shaped and include a shell which encloses a coil, an armature and a resilient member arranged in manner and form wherein the actuator is operable to cause the print wire to be axially moved a small precise distance in dot matrix printing.
In the case of a wire matrix printer which is utilized for form or multi-copy printing, the difference in thickness of the forms or copies may require some means or mechanism for adjusting the gap or the distance between the print head and the printer platen. It is in the field of printers and more specifically in the field of relatively small sized dot matrix printers for use in electronic cash registers (ECR), point of sale (POS) terminals or like registering-type machines that the subject matter of the present invention is most closely associated, which invention provides for improved and advantageous positioning and control of the slip or form between the print head and the printer platen for the printing operation.
There are requirements for use of the relatively small-sized dot matrix printers such as the slip or form printers that include small print stations having the capability of printing from 20 to 40 characters in the lateral or horizontal direction. These small printers are especially useful for installing or locating in relatively small and/or narrow places on a counter along with other peripheral devices.
While the print station of a conventional slip printer normally can accommodate the size and configuration of a conventional slip or form, there are recent developments in the data processing industry which require different arrangements for printing on other slips or forms. In the case of a conventional slip which is rectangular in shape and wherein such slip is inserted into the printer in the longitudinal direction, the width of the slip station is sufficient to accommodate the slip for printing in successive manner across the narrow dimension of the slip.
However, in association with recent developments of POS systems, the requirement has more frequently arisen that a document which has its long dimension in the horizontal direction such as a check, a slip or a form for credit card usage or the like is to be processed and printed in an ECR or a POS terminal. It is seen that to meet this requirement, it is necessary to enlarge or widen the print station to conform with the longitudinal direction of the slip. This, or course, enlarges the printer and additional space is needed on the counter.
The present invention has been contemplated in order to solve the above-mentioned problem of a larger printer requiring additional space.
Representative documentation in the field of wire matrix print heads includes U.S. Pat. No. 4,431,319, issued to N. Karaki et al. on Feb. 14, 1984, which discloses a serial dot printer for printing the same characters twice with a vertical distance between the first and second printing corresponding to half the vertical pitch of the dots in the first printing.
U.S. Pat. No. 4,521,123, issued to G. Boehmer on June 4, 1985, discloses representation of characters whose strokes comprise a central area, an ascender or a descender. The recording medium is displaced relative to the print element dependent upon the character strokes.
U.S. Pat. No. 4,543,644, issued to Y. Kozima et al. on Sept. 24, 1985, discloses a control circuit for a dot matrix printer that is suitable for various and desirable dot-print patterns.
Japanese Published Patent Specification No. 18989/81 entitled "Character Pattern Generator", discloses means by which dot patterns of turned characters are sequentially produced in single character or one character at a time manner by using a plurality of shift registers and AND gates.